Synergistic functional fluid compositions

ABSTRACT

Functional fluid compositions comprising at least one halogenated compound, certain phosphate esters and certain bright stock petroleum fractions which have excellent lubricity, fireresistance, and homogeneity and are particularly useful as lubricants and hydraulic fluids.

States Patent Street [15] 3,657,120 [451 Apr. 18, 1972 [54] SWNERGISTIC FUNCTIONAL FLUID CUMIPOSITIONS [72] Inventor: Robert W. Street, Clayton, Mo.

[73] Assignee: Monsanto Company, St. Louis, Mo.

[22] Filed: Aug. 1, 1969 [21] Appl. No.: 850,689

Related U.S. Application Data [63] Continuation-impart of Ser. No. 739,912, June 17, 1968, abandoned, which is a continuation of Ser. No. 497,195, Oct. 18, 1965, abandoned.

2,203,102 6/ 1940 Powers ..252/49.8

2,245 ,649 6/1941 Caprio 3,136,726 6/1964 Moreton ..252/49.9

OTHER PUBLICATIONS Egan, Lubricating Engineering Feb-Mar. 1947 pages 24, 25 and 26.

Gruse et a1., Chemical Technol. of Petroleum 3rd Edition 1960 pages 188-191, and 536 & 537.

ASTM, Standards of Petroleum Products and Lubricants Oct. 1959 pages 183- 186.

Primary Examiner-Daniel E. Wyman Assistant Examiner-W. Cannon Attorney-Neal E. Willis, J. E. Maurer and Wayne R. Eberhardt [57] ABSTRACT Functional fluid. compositions comprising at least one halogenated compound, certain phosphate esters and certain bright stock petroleum fractions which have excellent lubricity, fire-resistance, and homogeneity and are particularly usefit] as lubricants and hydraulic fluids.

16 Claims, 2 Drawing Figures I 'ISOOCTYL DIPHENYL PHOSPHATE lI-TRICESYL PHOSPHATE IlI-CRESYL DIPHENYL PHOSPHATE BRIGHT STOCK OIL HALOGENATED PHOSPHATE BIPHENYL ESTER BRIGHT STOCK OIL/PHOSPHATE ESTER/HALOGENATED BIPHENYL WEIGHT7 INVENTOR ROBERT W. STREET BY C ATTORNEY PATENTEDAPR 18 I972 3, 657'. 128

5 SHEET; 2 [1F 2 BRlGHT STOCK OIL VAVAA 7: A YAYAV AVAYYAY YV "i mm m/vvwvg ZQQ/VK/VVVVVV WWVW y mm/vw/vvm/vwm f" HALOGENATED PHOSP E BIPHENYL EST BRIGHT STOCK OIL/PHOSPHATE ESTERA- ALOGENATED BlPl-IENYL INVENTOR ROBERT W. sT

BY C WW/C.

ATTORNEY SYNIERGISTIC FUNCTIONAL FLUID COMPOSITIONS CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 739,912 filed June 17, 1968, which in turn is a continuation of application Ser. No. 497,195 filed Oct. 18, 1965 both of which applications are now abandoned.

BACKGROUND OF THE INVENTION lubricants, damping fluids, bases for greases, force transmission fluids (hydraulic fluids) and as filter mediums for air conditioning systems. Because of the wide variety of applications and the varied conditions under which functional fluids are utilized, the properties desired in a good functional fluid necessarily vary with the particular application in which it is to be utilized with each individual application requiring a functional fluid having a specific class of properties.

Of the foregoing, the use of functional fluids as lubricants and hydraulic fluids, particularly industrial lubricants and hydraulic fluids, has posed a difficult area of application. Increasing demands to improve the safety of industrial manufacturing as a whole has caused the extended use of fire-resistant fluids, e.g., fire-resistant lubricants and fire-resistant hydraulic fluids in a wide range of industries. The term fire-resistant fluid as used herein means a fluid of such chemical composition and physical characteristics that it will resist the propagation of flame under certain conditions hereinafter defined. At present there are four major classes of hydraulic fluids used in industrial hydraulic systems, which are petroleum oils, water/glycol solutions, water-in-oil emulsions and completely synthetic types. It is well known in the art that the ability of the fluid to resist flame propagation is one of degree. Fluids of the four types mentioned have varying degrees of fire-resistance and are" used in applications according to the severity of the conditions, taking into account such factors as degree of danger from fire, operating temperature, being loads and cost. Many synthetic fluids such as the aryl phosphate esters offer a high degree of fire resistance and are usually employed when the danger from fire is great. The cost of synthetic fluids has restricted their use to the most severe conditions. The water containing fluids, while offering an acceptable degree of fire resistance at low cost, are not desirable in systems operating at high temperatures or where good lubricity of the fluid is required or where danger from fire is great.

Petroleum oils, while offering good lubricity, are the least fire resistant but are used in many applications having a marginal fire hazard due to their low cost and general availability. Previous attempts to render petroleum oil more fire resistant by incorporating therein known fire-resistant compounds such as phosphate esters have not produced fluids having a generally acceptable combination of lubricity, fire resistance and homogeneity. Numerous proposals have been made for correcting one or another of these properties, but correction of one property is usually effected at the expense of another property. For example, the incorporation of alkyl phosphate esters in petroleum to improve fire resistance results in fluids of marginal hydrolytic stability. The aryl phosphate esters, while providing superior fire resistance and hydrolytic stability, can only be added in small amounts due to the limited miscibility of the esters in petroleum oils and such amounts are ineffective in producing any significant increase in fire resistance. Also, previously, aliphatic and olefinic chlorinated hydrocarbons have been combined with mineral oil to improve fire resistance; however, they have required either the use of only minor amounts of mineral oil thus not achieving economical fire-resistant compositions or the use of significant amounts of corrosion inhibitor because such chlorinated hydrocarbons tend to be corrosive to metals. The combination of approximately equal amounts of aryl phosphate esters and chlorinated hydrocarbons yields a fluid with good flame resistance and fair lubricity, but requires the addition of VI improvers to obtain a satisfactory viscosity index.

Low-cost, fire-resistant, homogenous petroleum-containing fluids overcoming the problems of the prior art fluids have now been discovered which not only provide superior lubricating capability but also a surprising degree of fire resistance at reasonable costs. It is therefore, an object of this in- SUMMARY OF THE INVENTION According to this invention, there are provided compositions useful as functional fluids which are comprised of (1) a petroleum bright stock oil having a viscosity range of from about 150 to about 250 SSU at 210 F., (2) a phosphate ester selected from the group consisting of an ester represented by the formula where R, R and R are each selected from the group consisting of phenyl radicals, substituted phenyl radicals and alkyl C radicals provided that not more than one of R, R and R is an alkyl radical, and mixtures thereof, and (3) halogenated compounds selected from the group consisting of halogenated benzenes, naphthalenes, biphenyls, terphenyls, perhalodienes and perhalocyclodienes having not less than four nor more than eight carbon atoms. The term halogens and halogenated as employed inthe specification and claims are intended to refer to one or more of the group consisting of chlorine, bromine and fluorine.

DESCRIPTION OF PREFERRED EMBODIMENTS 1. Bright Stocks The bright stocks useful in the compositions of this invention are those known in the art as conventionally refined of solvent extracted. In the refining of mineral oils, the crude oils are subjected to a first distillation under ordinary pressures to remove the low boilers, and a second steam distillation to remove heavy oil and waxy fractions. The residue from the steam distillation is known as steam refined stock" or cylinder oil. This material is subsequently deasphalted and dewaxed and treated with solvents and clays to produce the product known as bright stock.

The bright stocks are most generally used as heavy gear lubricants, and for blending with neutral oils for automatic engine lubricants. While the bright stocks can have a viscosity in the range of from about 50 to about 300 SSU at 210 F., those which are useful in the compositions of the present invention have viscosities in the range of about 150 to 250 SSU at 210 F and preferably in the range of 200 to 220 SSU at 210 F.

The bright stocks are not to be confused with the lower viscosity mineral oils, which generally have viscosities in the range of 45 to SSU at 210 F., as shown below.

Viscosity Ranges of SAE Grade Oils Centistokes (CS) Saybolt Seconds (550) 2. Phosphate Esters Phosphate esters useful in compositions of this invention are the alkyl diaryl and the tri-aryl phosphate esters which may contain substituted and unsubstituted phenyl radicals. Such substituents can be alkyl C radicals, chlorine, bromine or fluorine and haloalkyl C radicals. In the case of alkyl or haloalkyl substituted phenyl radicals up to three positions on the ring can be occupied whereas as many as four positions can be substituted by chlorine, bromine or fluorine. Typical examples of alkyl diary] phosphate esters useful in compositions of this invention are ethyl diphenyl phosphate, propyl diphenyl phosphate, butyl diphenyl phosphate, pentyl diphenyl phosphate, hexyl diphenyl phosphate, octyl diphenyl phosphate, nonyl diphenyl phosphate, tridecyl diphenyl phosphate, dodecyl diphenyl phosphate, octadecyl diphenyl phosphate, pentadecyl diphenyl phosphate, preferably osooctyl diphenyl phosphate and 2-ethylhexyl diphenyl phosphate.

Typical examples of tn'aryl phosphate esters include triphenyl phosphate tris-m-difluorophenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, m-chlorophenyl dicresyl phosphate, m-chlorophcnyl diphenyl phosphate, xenyl diphenyl phosphate, trixenyl phosphate, m-chlorophenyl diphenyl phosphate, perfluoromethylphenyl diphenyl phosphate, e, m-fluorophenyl diphenyl phosphate, tris-m-butylphenyl phosphate and bromophenyl diphenyl phosphate.

The phosphate ester components of compositions of this invention can also be a mixture of esters comprising at least one ester represented by Formula 1 above and at least one other phosphate ester which can be either trialkyl or dialkyl aryl provided the resulting mixture contains an alkyl ester group to aryl ester group ratio which does not exceed 1.5 to 1 respectively. For example, a composition of this invention can be prepared wherein the phosphate ester component is a mixture of tris-n-butyl phosphate and isooctyl diphenyl phosphate in a weight ratio of l to 2 respectively. Such a mixture of phosphate esters provides an alkyl group to aryl group ratio of slightly less than 1.5 to 1 respectively. These same exemplary esters, when employed in a weight ratio of l to 4 respectively, would provide an alkyl group to aryl group ratio of slightly less than 1 to l with the aryl groups slightly in excess.

Typical dialkyl aryl esters which can be used in admixture with the above-described esters are dipropyl phenyl phosphate, di-n-butyl phenyl phosphate, di-tert.-butyl cresyl phosphate, di-n-butyl chlorophenyl phosphate, dipentyl phenyl phosphate, diethyl bromophenyl phosphate, dioctyl phenyl phosphate, dioctyl cresyl phosphate, didecyl phenyl phosphate and dioctadecyl phenyl phosphate. The aryl group of the dialkyl aryl phosphates may contain one or two substituent groups on the aryl nucleus selected from methyl and halide radicals. Typical alkyl phosphates which can be used are tri-n-propyl phosphate, tri-tert.-butyl phosphate tri-isobutyl phosphate, tri-2-ethylhexyl phosphate, tricapryl phosphate, tridecyl phosphate, tris-tridecyl phosphate and trioctadecyl phosphate, tris (m-tert-butyl phenyl) phosphate, 2,3,5- triethylphenyl dixenyl phosphate.

3. Halogenated Compounds the halobenzenes useful in compositions of this invention are those represented by the formula where D is selected from the group consisting of chlorine, bromine and fluorine, andfis an integer from 2 to 4.

Typical examples of halobenzenes useful in compositions of this invention are o-dibromobenzene, l-bromo-3- chlorobenzene, l,3-dichloro-5-bromobenzene, 1,3difluoro-5- bromobenzene, l-fluoro-3-chloro-5-bromobenzene, 1,2,3,4- tetrafluorobenzene, l,3-dibromo-3,S-dichlorobenzene, 1,3- dibromo-4,6-difluorobenzene, trifluorobenzene and preferably mdibromobenzene. Also useful are mixtures in all proportions of halobenzenes containing the same or different halogens. For example, a mixture of m-dibromobenzene and 1,2,4-trichlorobenzene can be used as the halogenated hydrocarbon in the compositions of this invention. In addition, mixtures of chlorobenzenes are particularly useful in compositions of this invention. Such mixtures can contain by weight from about 40 percent to about percent tetrachlorobenzene and from about 20 percent to about 80 percent trichlorobenzene. Such mixtures can also contain pentachlorobenzene in small amounts ranging up to about 20 percent by weight. Exemplary mixtures of triand tetrachlorobenzenes are as follows:

Component Weight 70 A l,2,3,4-tetraehlorobenzene 40-50 l,2,4,5-tetrachlorobenzene 4-10 l,2,4-trichlorobenzene 25-35 l,2,3-trichlorcbenzene 0-3 pentachlorobenzene 10-20 B l,2,3,4-tetrachlorobcnzene 26-29 l ,2,4.5-tetrachlorobenzene 3 trichlorobenzene 58.5

pentachlorobenzene 5.5

C l,2,3,4-tetrachlorobenzene 26.9

l,2,4,S-tetrachlorobenzene 2.6

l ,2,4-trichlorobenzene 53.5

1,2,3-trichlorobenzene 9.7

pentachlorobenzene 5.3

impurities 2.0

Because of solubility characteristics the l,2,4,5-isomer of tetrachlorobenzene is not normally employed in large amounts. In addition, such mixtures of triand tetrachlorobenzenes are normally employed in amounts of up to about 50 percent of the total composition for most uses although amounts up to about 75 percent can be used when operating temperatures remain above C.

The perhalodienes and perhalocyclodienes useful in this invention are those compounds having at least four and not more than eight carbon atoms in the molecule. Typical perhalodienes are perchlorobutadiene, perbromobutadiene, perfluorobutadiene, perchloropentadiene, perfluoropentadiene, perbromopentadiene, perchlorohexadiene, perbromohexadiene, perchloroheptadiene, perchlorooctadiene, perbromooctadiene and perfluorooctadiene. Perchlorobutadiene is preferred. Typical perhalocyclodienes are perchlorocyclobutadiene, perfluorocyclobutadiene, perchlorocyclopentadiene, perbromocyclopentadiene, perfluorocyclopentadiene, percl'tlorocyclohexadiene, perbromocyclohexadiene, perchlorocycloheptadiene, perchlorocyclooctadiene and perfluorocyclooctadiene.

The halogenated naphthalenes useful in compositions of this invention are those represented by the formula uunan tachloronaphthalene, l-bromonaphthalene, 1,3- imum concentrations of typical phosphate esters having less dibromonaphthalene, l,5-dibromonaphthalene, 1,3,5- than 10 alkyl carbon atoms and providing compositions tribromonaphthalene, hexabrornonaphthalene, ochomogeneous at 70 F. are illustrated by lines I, isoctyl tabromonaphthalene, l-fluoronaphthalene, 1,4- diphenyl phosphate, II, tricresyl phosphate, III, cresyl diphenyl difluoronaphthalene, 1,3,5-trifluoronaphthalene and oc- 5 phosphate, in FIG. I, which lines are 70 F. isotherms indicattafluoronaphthalene. ing maximum weight percent amounts of such esters. Thus,

Also within the scope of this invention are halogenated the compositions of this invention which are homogenous at naphthalenes containing more than one specie of halogen in 70 a hi h nta isooctyl p y p p a the same m l le a d mixtures f one or more f tricresyl phosphate and cresyl diphenyl phosphate are defined halogenated naphthalenes wherein the combined halogen 10 by the F Withlh the curves AFF'Ci AEE'C and content represents a degree of substitution of from one to respeehvetyi h h l atoms It has also been discovered that the components (l), (2),

The halogenated biphenyl and terphenyl compounds useful and f h comhlhed Pe P P in compositions of this invention can contain chlorine fluorine Produce fuhetloihat thhds havlhg surpl'lslhgty Smelt rates of or bromine or combinations thereof in amounts corresponding e e of vlseoelty t ehehge of temperature, f' P p to mono-, in the case of bromine only, di-, tri-, tetra-, pentaty h qeslfabte flhds e h as lubhcahts h as and hexahalobiphenyl Typical f such bipheny] compounds hydraulic fluids This property is highly unexpectedrn view of are the chlorinated biphenyls commercially available as the relahvely rates 9 hh of whh tempera products containing 32 percent, 42 percent, 48 percent, 45 fohhd some ofthe lhdwldhal e h h percent, and 60 percent by weight of combined chlorine and Thus Preferred cempeshlohs t thts hh/ehhoh whleh have a chlorinated terphenyls containing from about 20 percent to e rate h e ofylscoslty whh ehahge eftemperathre as about 70 percent by weight of combined chlorine. The expresmdlcated h f h h are those cohtahhhg (la) bnght sion halogenated biphenyl or terphenyl containing a stated stocks havlhg a 'h of at least about Preferably percentage of combined halogen is used herein as including about 95 and a i the range of from about 9 to the directly halogenated products, halogenated products conh 250 S at 210 phosphate esters as descnhed mining more than on: Specie of halogen in the Same molecule hereinabove in Formula I with the exception that the alkyl and and blends of one or more of such halogenated products haloalkylsubsmuems oh the arylmdtcals can cohtam no more whereby the halogen content is broadly within the range of 22: 3 sg s g g f g gggg i i i about percent to 60 percent, preferably within the range of 30 gombined b gz g g g g if about 30 percent to 42 percent by weight. Halogenated this g fr e 5 o quaterphenyl may also be present in small amounts up to mvhmlon contain oma percent ma out about 5 percent by weight Such minor amounts of cent bright stocks, from about 5 percent to about 44 percent halogenated quaterphenyl do not significantly alter the phosghate esterdand from Z 'g 25 zp jp characteristics of the compositions of this invention. f i g i zggg g g f z gg ihg g lgg fig Compositions of this invention in general terms contain, by FIG H which :Eg weight yercem of oneems 32; weight, from about 12 percent to about 65 percent bright and re uired to p referred ositions i z a i g to tg i i g i this invention. Tli us preferred comgositions of invention es er an rom a ou percen o a ou percen halogenated compound with each component present within 40 ffg f g fiiggz ggg gf ggg s j gg f their respective ranges so that the total of the three comobtained (ml when such com ems are resent in certain ponents is 100 percent. The compositions of this invention can c riti 6 a1 amogms which are gg b g area within the be more readily determined by reference to FIG. I which curve AFGIG ofFlG H y Shows the weight percent of components and (3) Preferred compositions of this invention include those required to produce the compositions of this invention. Thus, which contain by weight from about 25 percent to about 45 while h componehts. and (3) used to provide the percent of a bright stocli having a viscosity in the range of 9 of thls mvhmlon can combined fairly from about 150 to 250 SSU at 210 F. and a viscosity index of wlde range of prohomons' the 9? cothbthahoh of at least about 90, from about 10 percent to about 15 percent homogeneity, fire resistance and synergistic lubricity characof an alkyl cmrdiaryl phosphate and from about 40 percent teristic of such compositions is only obtained when such comto about 60 percent ofa chlorinated biphenyl containing from ponents are present in certain amounts which are defined by about 30 percent to about 54 percent, by weight combined the area within the curve ABC of FIG. I. chlorine While homogeneity at a temperature of at least about 150 wh i l phosphate esters are employed, preferred his obtained w pl y y Phosphate described above compositions having weight percent proportions of (1a), (2a), in any amount included in the area defined by the curve ABC 55 and (3a) within the are of the curve AFG'G of FIG H have a in FIG. 1, functional fluids are desirably homogeneous at room viscosity index rating f at least about +2 and when alkyl temperature, n about when Ph p esters aryl phosphate esters are employed viscosity index ratings of havlhg less than about 10 alkyl carbon atoms In the e h i at least about +35 are obtained. Viscosity measurements of ile the amounts of Such esters must be further hmlted lustrative preferred compositions of this invention were made with n the area defined by the curve ABC of FIG. I in order to according to ASTM M h d 13.445-54'1" using a C Provlde compositions Whleh are homogeneous at room Fenske modified Ostwald viscometer and are set forth in perature- More Specifically, m Such Phosphate esters the alkyl Table 1 below in centistoke units. The viscosity indices appeareal'bohs can be located in a Single ester group, distributed ing in Table l were determined according to ASTM Method among y ester groups as substituents on the y nucleus or D567-53. The amounts of each component listed in Table I divided between aryl substituents and alkyl ester groups. Maxare i i h percent f h fi l composition TnBLE I Viscosity, cs. V t Component F. 210 F. ih iieii (a) Bright stock oil 200 SSU at 210 s4 42. 0 +94 (b) Chlorinated biphenyl, 42 percent Cl. 17.0 2. 45 215 (c) Chlorinated biphenyl, 48 percent Cl 44. 06 20 625 E39 essences a 122 0:1: Q-ethylhexyldicresylphosphate:II: 15:94 3ih6 +25 'l'ahlc l ('onlinucd Viscosity ((fS.) Viscosity (05.) measured calculated Weight puroont ol components 100 210 100 210 No. (a) (b) (c) (d) (c) (t) F. VI F. F. V!

l 4. 99 +40. 5 28 3. 9 38 2. 5. 02 +56. 5 35 4. 3 55 3. 6. 74 +56. 43 4. 7 57 t. l3. l +92 120 10.3 +66 5. 5. 85 +45 49 4. 9 69 (L 5. 80 +22 37 4. 3 8l 7. 6. 37 +42 40 4. 5 70 8. 7. 50 +54. 5 50 5. 3 9 t! 5. 38 +37 30.8 4. 0 -62 As indicated in Table l, surprisingly and unpredictably high viscosity indices are obtained with the preferred compositions of this invention in view of the extremely low viscosity indices of the components making up the major weight percent amounts of the compositions, and in view of the low viscosity indices calculated according to the procedure given in ASTM D-34l-43. Also, it is to be noted that these relatively high readings were obtained without the use of viscosity index improvers. Commonly used viscosity index improvers such as the methacrylates and polyalkylacrylates are known to possess inferior shear stability which is imparted to the base fluid to which they are added. Thus, yet another advantage is seen in the preferred compositions of this invention in that good viscosity characteristics are obtained without sacrificing the shear stability of the fluid by the use of viscosity index improvers. In some instances, however, it may be desirable to add viscosity index improvers when a higher viscosity index is more important than shear stability.

The shear stability of one preferred composition of the present invention was determined by means of a Raytheon sonic oscillator, Model DF-lOl, wherein the composition was maintained at about 100 F. for a period of 2 hours under irradiation while samples were taken at intervals over a 2hour period. The test was repeated with a hydraulic fluid of the prior art which contained a Vi improver. The fluid compositions, and the results of the test, were as follows:

Fluid 1. Composition of the present invention 3am Bright stock, 200 ssu at 2t2 F.

47.5% Chlorinated diphcnyl (42% Cl) I49; isooctyl diphcnyl phosphate Example of prior art 45% Tricrcsyl phosphate 52.5% Chlorinated diphenyl (48% Cl) 2.5% Polyalkyl methacrylate-petroleum oil V.l.

improver (Acryloid 710, a product of the Rohm and Haas Co., Philadelphia. Penn.)

Fluid 2.

Sonic Shear Test Results 1 1 AS'IM Procedure, vol. 1, October 1961, p. 1160 Proposed Method of Test for shear FEWHEKTPPWPE.will

It is clearly evident from the above data that the fluid compositions of the present invention is considerably more shear stable than the fluid of the prior art.

Another of the unique features of the compositions of this invention is that while each of the components of such compositions has fairly good lubricating ability, the compositions defined by the area within the curve ABD of FIG. I possess greater lubricating ability than any of such components. The surprising synergistic lubricating properties found in the compositions of this invention are demonstrated by the data contained in Tables ll and ill below. These data were obtained using a "Timken Extreme Pressure Lubricant Testing Machine, which is a machine designed to determine the ability of a lubricant to prevent a test block from being seized or abraded by a rotating, tapered roller bearing (test cup) under a known load. The test block and test cup are in lubricated contact with each other during a test period of ten minutes during which time the bearing is rotated at 810 R.P.M. under a known load. After the test period the machine is stopped and the test block inspected. A new test block and test cup is installed and if no evidence of seizure or abrasion is found on the previously used test block, the test is repeated with a 5- pound increase in load. The procedure is repeated until damage to the test block is observed. If seizure or abrasion is observed on the first run, the test is repeated with five pound incremental decreases in the load until no damage to the test block is observed. The highest load run without observing damage to the test block is reported as the maximum load, in pounds. Table II, below, contains the data thus obtained when individual components of the compositions of this invention were employed as the lubricant. In Table III, data are presented from test runs employing typical examples of compositions of this invention. In each instance except Test Composition No. 4, a Mid-Continent bright stock oil having a viscosity of 200 SSU at 210 F. was used. in Test Composition No. 4 a Mid-Continent bright stock oil having a viscosity of 220 SSU at 210 F. was employed.

g) Mixture of Triand Tetrachlorobenzene (Approx. 50/50) Contains, by weight, 23% chlorinated terphenyl and 2% chlorinated quaterphcnyl.

1 SSU at 210 F. viscosity. 1 Composition was non-homogeneous at test tmnpt-raturv.

The data contained in Table Ill is divided into three areas as follows:

Samples l-l 3: three component compositions included within the scope of this invention,

Samples 14-21: two component compositions not included within the scope of this invention,

Samples 22,23: three component compositions not included within the scope of the present invention.

A comparison of the test data presented in Tables II and Ill clearly show the follpwing:

l. the maximum load carrying ability of the individual components in Table II ranges from to 45 pounds,

2. the maximum load carrying ability of two component mixtures according to samples 14-21 (Table III) range from to 55 pounds,

3. the maximum load carrying ability of the three com Two tests were used for the measurement of the fire-resistance of the instant fluids since there is no single test that can be used to evaluate all types of fluids under all expected use conditions. The degree of fire-resistance in any given test is influenced by the characteristics of the fluid, the physical state of the fluid and many other factors. One of the tests was designed to simulate conditions resulting from a broken line spraying hydraulic fluid into various sources of ignition and is known as the High-Pressure Spray Test. An additional test often used, which is a smaller scale test, is the Molten-Metal Pour Test. In this test the fluid under evaluation is dropped from a medicine dropper or poured from a calibrated test tube onto the surface of molten aluminum alloy which has been heated to about l,250 F. Ifspontaneous ignition does not occur, a spark is placed in the vapors to determine if they can be ignited.

TABLE IV.-FIRE-RESISTANCE TESTS Weight percent Viscosity. cs.. atof com- N 0. Composition components ponents F. 100 F. 210 F. High pressure spray test Molten Aluminum test. 1.250 F.

Bright stock 200 SSU at 210 F 40. 0 Does not flash up to 6 it. (1) Does not burn without spark Chlorinated biphenyl 42% com- 46.0 from orfice. At 6 ft. flames (2) Flashes with a spark but is self 1 bmed chlorine. 930 70. 6 7. 8 carry about 6 inches from extinguishing until half of fluid is va- Isooctyl diphenyl phosphate 14.0 tip of torch. porized then flashes and burns to completion.

Bright stock 200 SSU at 210 F 25 Does not flash up to 6 it. (1) Does not burn without spark. (2) Chlorinated biphenyl 42% comfrom orfice. At 6 it. flames Flashes with a spark but is self ex- 2 bined chlorine. 61.0 532 39.5 5.1 carry about 6 inches from tinguishing until half of fluid is va- Isooctyl diphenyl phosphate 14. 0 tip of torch. porized then flashes and burns to completion.

Does not flash up to 6 ft. (1) Burns to completion without spark Water/oil emulsion: 1 100 W) W from oriliee. At. (i it. after water bolls oil. (2) Burns to Witter 40 llnrnes curry 4 to ii lnehes completion with spnrk utter water ()ll (ill il'OilI tip of toreii. hells oil.

Wnter/glyrol solution: Does not llnsh up to 6 it. (1) iinrns' to completion without spark 4 Water 40 300 60 14 from oriliee. At 6 it. from after water holls oil. (2) Burns to Glycol. 60 orifice flames carry 4 to 6 completion with a spark after water inches from tip of torch. boils ofl.

chlofillilted p y 67 No flashes up to 6 it. from (1) Does not flash or burn without a 5 combined chlorine. 4 000 30 2 85 orifice. At 6 it. flames spark. (2) Flashes with a spark but Chlorinated biphenyl. 42% 33 carry about 6 in. from is self extinguishing.

combined chlorine. tip of torch.

Occasional flashing at about (1) Does not flash or burn without a 6 Triaryl phosphate 100 450 32 4, 2 4 it. from orifice with spark. (2) Flashes with a spark but is flames carrying about 2 it. self extinguishing. from tip of torch.

lreininln wtreienni oil 100 500 48 6.7 Fluid ignited 12 inches ignites without it spark and burns to y lrnnllr llnld. llOlll orillee with eontincompletion.

nous llnnles enrrylng 10 it. from tip of torch.

ponent mixtures included within the scope of the instant in- 50 in addition to the above, the compositions of this invention vention as exemplified by samples 1-13 (Table ill) range from 50 to 65 pounds.

4. the maximum load carrying ability of typical three component mixtures lying outside the limits of the present invention (samples 22 and 23 of Table III) is significantly less than that of the compositions of this invention.

From a comparison of items (2) and (3) above, it is evident that a synergistic effect equivalent to at least an additional 10 psig orabout a 20 percent increase in load bearing capacity is obtained with the three component mixtures defined by the present invention, and that the high load carrying capacity of these compositions could not be predicted on the basis of the single fluid or two component fluid test results.

Another property of the unique compositions of this invention is their outstanding fire resistance even though they contain significant amounts of flammable bright stock. To illustrate the fire resistance of the compositions of this invention their typical properties and the properties of other commercially used fire-resistant hydraulic fluids are set forth in Table IV below. The test procedures used to measure the various properties of the fluids of this invention and those used as comparisons are as follows:

Viscosity High Pressure Spray Test are not prone to foaming and any foam formed is not stable. Furthermore, the claimed compositions have good stability, even at temperatures of 250 F. and in the presence of air, and are essentially noncorrosive to metals such as aluminum, aluminum bronze alloy, iron, silver and titanium. A further advantage of the instant compositions is their outstanding hydrolytic stability.

As a result of the excellent physical properties of the fluids particularly described in the proceeding examples, improved hydraulic pressure devices can be prepared in accordance with this invention which comprise in combination a fluid chamber and an actuating fluid insaid chamber, said fluid comprising one of the compositions hereinbefore described. in such a hydraulic apparatus wherein a movable member is actuated by the above-described functional fluids, performance characteristics are obtainable which are superior to those heretofore obtainable.

Because of the excellent fire-resistance of the compositions of this invention and good lubricity, they can be utilized in those hydraulic systems wherein power must be transmitted and the frictional parts of the system lubricated by the hydraulic fluid utilized. Thus, the novel functional fluids of this invention find utility in the transmission of power in a hydraulic system having a pump therein supplying the power for the system. in such a system, the parts which are so lubricated include the frictional surfaces of the source of power, namely the pump, valves, operating pistons and cylinders, fluid motors, and in some cases, for machine tools, the ways, tables and slides. The hydraulic system may be of either the constant volume or the variable volume type.

The pumps may be of various types, including the pistontype pump, more particularly the variable-stroke piston pump, the variable-discharge of variable displacement piston pump, radial-piston pump, axial-piston pump, in which a pivoted cylinder block is adjusted at various angles with the piston assembly, for example, the Vickers Axial-Piston Pump, or in which the mechanism which drives the pistons is set at an angle adjustable with the cylinder block; gear-type pump, which may be spur, helical or herringbone gears, variations of internal gears, or a screw pump; or vane pumps. The valves may be stop valves, reversing valves, pilot valves, throttling valves, sequence valves or relief valves. Fluid motors are usually constant or variable discharge piston pumps caused to rotate by the pressure of the hydraulic fluid of the system with the power supplied by the pump power source. Such a hydraulic motor may be used in connection with a variable-discharge pump to form a variable speed transmission.

In addition to the above, compositions of this invention can be utilized as gear lubricants in mechanical power trains. Mild mineral oil E.P. gear lubricants currently employed commercially provide ratings within the ranges of 45 to 65 pounds when tested by the Timken Extreme Pressure Lubricant Testing Machine described above and typical para-ffrnic petroleum oil employed as a gear lubricant having a viscosity of about 300 SSU at 100 F. provide ratings in the range of only to pounds. Accordingly, in view of the high ratings reported in Table ill (50 to 65 pounds), compositions of this invention can be used alone or in combination with lubricant adjuvants as lubricants in automotive and other mobile equipment power trains. Also, compositions of this invention are heavier than water thus making their use as gear lubricants even more desirable in applications such as in sheet metal rolling mill power trains where water contamination is likely. This property allows water contamination to be more easily removed by flotation of the water and renders such water contamination less harmful than in prior lubricants containing mineral oil.

The compositions of this invention can also contain dyes, pour point depressants, antioxidants, viscosity index improvers, such as polyalkylacrylates and polyalkylmethacrylates, anti-rust agents, hydrolytic stabilizers and the like where ever desired for special use requirements.

While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

What is claimed is: l. A composition comprising a mixture of l. a bright stock having a viscosity in the range of from about 150 to about 250 SSU at 210 F., 2. a phosphate ester selected from the group consisting of an ester represented by the formula where R, R and R are each selected from the group consisting of phenyl, alkyl C radicals, and phenyl radicals substituted with halogen, alkyl C radicals, or haloalkyl C radicals, provided not more than one of R, R and R is alkyl, and mixtures thereof, and,

3. halogenated biphenyls containing from about percent to about 60 percent by weight halogen and mixtures thereof, wherein the amounts of (l), (2), and (3) are within the area defined by the curve ABC of FIG. I.

2. A composition of claim 1 where the halogenated compound is chlorinated biphenyl containing from about 30 percent to about 60 percent by weight combined chlorine.

3. A composition of claim 1 where the phosphate ester is an alkyl diaryl phosphate.

4. A composition of claim 3 where the phosphate ester is selected from the group consisting of Z-ethyl-hexyl diphenyl phosphate, isooctyl diphenyl phosphate, and cresyl diphenyl phosphate.

5. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim 1.

6. A composition comprising a mixture by weight of from about 25 percent to about 45 percent of a bright stock having a viscosity in the range of from about to 250 SSU at 210 F. and a viscosity index of at least about 90, from about 10 percent to about 15 percent of an alkyl C diaryl phosphate and from about 40 percent to about 60 percent of a chlorinated biphenyl containing from about 30 percent to about 54 percent, by weight, combined chlorine.

7. A composition of claim 6 where the bright stock has a viscosity in the range of from about 200 to 220 SSU at 210 F. and a viscosity index of at least about 95.

8. A composition of claim 6 where the phosphate ester is selected from the group consisting of isooctyl diphenyl phosphate and ethyl hexyl diphenyl phosphate.

9. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim 6.

10. A composition comprising a mixture of 1. bright stock having a viscosity in the range of from about 150 to 250 SSU at 210 F., 2. a mixture of phosphate esters comprising (i) at least one ester represented by the formula where R, R and R are each selected from the group consisting of phenyl, alkyl C radicals, and phenyl radicals substituted with halogen, alkyl C radicals, or haloalkyl C radicals, provided not more than one of R, R and R, are alkyl and (ii) at least one ester selected from the group consisting of trialkyl C phosphates and idalkyl C aryl phosphates, the maximum ratio of alkyl ester groups to aryl ester groups being about 1.5 to 1 respectively; and

3. halogenated biphenyls containing from about 30 percent to about 60 percent by weight halogen and mixtures thereof, wherein the amounts of l (2), and (3) are within the area defined by the curve ABC of FIG. 1.

11. A composition of claim 10 where the bright stock has a viscosity in the range of from about 200 to 220 SSU at 210 F.

12. A composition of claim 10 where the mixtures of phosphate esters comprises at least one alkyl diary] phosphate and at least one trialkyl phosphate.

13. A composition of claim 17 where the mixture of phosphate esters comprises at least one triaryl phosphate and at least one trialkyl phosphate.

14. A composition of claim 10 where the halogenated compound is chlorinated biphenyl containing from about 30 percent to about 60 percent, by weight, combined chlorine.

15. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim 10.

16. A composition comprising, by weight, about 40 percent bright stock having a viscosity of about 200 SSU at 210 F., about 14 percent isooctyl diphenyl phosphate and about 46 percent chlorinated biphenyl containing about 42 percent chlorine. 

2. a mixture of phosphate esters comprising (i) at least one ester represented by the formula
 2. a phosphate ester selected from the group consisting of an ester represented by the formula
 2. A composition of claim 1 where the halogenated compound is chlorinated biphenyl containing from about 30 percent to about 60 percent by weight combined chlorine.
 3. A composition of claim 1 where the phosphate ester is an alkyl diaryl phosphate.
 3. halogenated biphenyls containing from about 30 percent to about 60 percent by weight halogen and mixtures thereof, wherein the amounts of (1), (2), and (3) are within the area defined by the curve ABC of FIG. I.
 3. halogenated biphenyls containing from about 30 percent to about 60 percent by weight halogen and mixtures thereof, wherein the amounts of (1), (2), and (3) are within the area defined by the curve ABC of FIG.
 1. 4. A composition of claim 3 where the phosphate ester is selected from the group consisting of 2-ethyl-hexyl diphenyl phosphate, isooctyl diphenyl phosphate, and cresyl diphenyl phosphate.
 5. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim
 1. 6. A composition comprising a mixture by weight of from about 25 percent to about 45 percent of a bright stock having a viscosity in the range of from about 150 to 250 SSU at 210* F. and a viscosity index of at least about 90, from about 10 percent to about 15 peRcent of an alkyl C2-18 diaryl phosphate and from about 40 percent to about 60 percent of a chlorinated biphenyl containing from about 30 percent to about 54 percent, by weight, combined chlorine.
 7. A composition of claim 6 where the bright stock has a viscosity in the range of from about 200 to 220 SSU at 210* F. and a viscosity index of at least about
 95. 8. A composition of claim 6 where the phosphate ester is selected from the group consisting of isooctyl diphenyl phosphate and ethyl hexyl diphenyl phosphate.
 9. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim
 6. 10. A composition comprising a mixture of
 11. A composition of claim 10 where the bright stock has a viscosity in the range of from about 200 to 220 SSU at 210* F.
 12. A composition of claim 10 where the mixtures of phosphate esters comprises at least one alkyl diaryl phosphate and at least one trialkyl phosphate.
 13. A composition of claim 17 where the mixture of phosphate esters comprises at least one triaryl phosphate and at least one trialkyl phosphate.
 14. A composition of claim 10 where the halogenated compound is chlorinated biphenyl containing from about 30 percent to about 60 percent, by weight, combined chlorine.
 15. In the method of operating a hydraulic pressure device wherein a displacing force is transmitted to a displaceable member by means of a hydraulic fluid, the improvement which comprises employing as said hydraulic fluid a composition of claim
 10. 16. A composition comprising, by weight, about 40 percent bright stock having a viscosity of about 200 SSU at 210* F., about 14 percent isooctyl diphenyl phosphate and about 46 percent chlorinated biphenyl containing about 42 percent chlorine. 